Alzheimer's disease is a condition typically associated with older individuals, and diagnosis is not usually made until symptoms appear later in life. But new research suggests that people who are free of dementia but have two parents with Alzheimer's may show signs of the disease in brain scans decades before symptoms appear.
This is according to a study recently published online in the journal Neurology.
The research team, including Lisa Mosconi of the New York University School of Medicine, analyzed 52 individuals aged between 32 and 72 who were free of dementia.
All participants were divided into four groups. These consisted of individuals who had either a mother with Alzheimer's disease, a father with the condition, both parents with the disease, or no family with the condition.
A series of brain scans were carried out on all subjects, including positron emission tomography (PET) and magnetic resonance imaging (MRI).
MRI scans show images of brain structure and potential reductions in brain volume, while PET scans measure overall brain activity and the amount of brain plaques.
Genes 'could predispose development of Alzheimer's disease'
Results of the study revealed that participants whose mother and father both had Alzheimer's disease showed 5-10% more brain plaques in specific brain regions and more severe brain abnormalities in brain volume and metabolism, compared with people who had one parent or no family members with Alzheimer's disease.
Results of PET and MRI scans showed that participants whose parents both had Alzheimer's showed 5-10% more brain plaques in specific brain regions, compared with participants with only one parent or no family member affected by the disease.
The researchers also found that individuals who had mothers with Alzheimer's disease showed a higher level of biomarkers of the condition in their brain scans, compared with people who had fathers with Alzheimer's disease.
The investigators note that this finding supports previous research showing that individuals who have mothers with Alzheimer's disease are more likely to develop the condition, compared with people who have fathers with the disease.
The investigators say the findings suggest there could be genes that predispose the development of Alzheimer's disease for each person, dependent on whether one or both parents have the condition.
"We do not yet know which genes, if any, are responsible for these early changes, and we hope that our study will be helpful to future genetic investigations," adds Mosconi.
According to the Alzheimer's Association, more than 5 million Americans are living with Alzheimer's disease, and it is the sixth leading cause of death in the US.
The investigators stress the importance of early detection for Alzheimer's disease.
"Studies show that by the time people come in for a diagnosis, there may be a large amount of irreversible brain damage already present.
This is why it is ideal that we find signs of the disease in high-risk people before symptoms occur."
Medical News Today recently reported on a study suggesting that concussion history could contribute to the development of Alzheimer's disease.